Taxonomy and survey of retransmission-based partially reliable transport protocols

Abstract

The mismatch between the services offered by the two standard transport protocols in the Internet, TCP and UDP, and the services required by distributed multimedia applications has led to the development of a large number of partially reliable transport protocols: protocols that in terms of reliability place themselves between TCP and UDP. This paper presents taxonomy for retransmission-based, partially reliable transport protocols, i.e. the subclass of partially reliable transport protocols that makes error recovery through retransmissions. The taxonomy comprises two classification schemes: one that classifies protocols with respect to the reliability service they offer and one that classifies them with respect to their error control scheme. The objective of our taxonomy is fourfold: to introduce a unified terminology; to provide a framework in which this class of protocols can be examined, compared and contrasted; to make explicit the error control schemes used by these protocols; and, finally, to gain new insight into these protocols and thereby suggest avenues for future research. Based on our taxonomy, a survey is made of existing retransmission-based, partially reliable transport protocols. The survey shows how protocols are categorized according to our taxonomy and exemplifies the majority of reliability services and error control schemes detailed in our taxonomy. © 2004 Elsevier B.V. All rights reserved.